macOS 11 Big Sur includes major user interface updates. The overall appearance of the operating system is lighter, more colorful, and more spacious. The application and Finder windows have a full-height sidebar, the Dock has a new "floating" look, and the menu bar is more translucent. Most app icons have been completely redesigned.
Big Sur is the first version of macOS to include Control Center, which consolidates common settings, such as Wi-Fi, Bluetooth, display, and sound options into a single area. It also includes an updated version of Notification Center, which supports interactive notifications, grouping notifications, and custom widgets, such as Calendar, Weather, and Notes. Big Sur maintains most of the utilities bundled with previous versions of macOS, but removes the Network Utility app.
Apple made significant updates to several bundled applications in Big Sur, including Safari, Mail, Messages, Music, and Maps. Many updates are designed to provide a more seamless user experience between iOS and macOS. For example, Messages in Big Sur supports pinned conversations, "mentions" of individual users, inline replies, animated GIFs, and message effects.
NOTE: Unlike the previous 16 versions of OS X or macOS, which carried the "Mac OS 10" name, Big Sur is "macOS 11." In Big Sur, minor point updates now use the standard "minor point number" in the version, such as 11.1, 11.2, etc. Previous versions of macOS used the "patch number" for minor point updates, such as (OS X Mavericks 10.9.1, 10.9.2, etc.
Updated: May 21, 2021